Get MII login name without applets

We have been modifying our MII pages to minimize use of applets and maximize use of AJAX.

With the example Javascript code I have, there is one thing I don't know how to do: get the UserID of the logged-in user without the use of applets.

With any applet on the page, I can use this syntax:
var username = document.[AppletName].getPropertyValue("IllumLoginName");

How can I do the same thing without the use of applets?

Thanks,

Greg